This invention relates to a method of locking metal terminals in a connector used for connecting, for instance, harnesses in a motor vehicle, and a device for practicing the method (hereinafter referred to as "a terminal locking method", and "a terminal locking device", respectively, when applicable).
An example of a conventional terminal locking device of this type, as shown in FIG. 8, is of 4-pole type; and comprises: a housing a; and a terminal locking element b. The terminal locking element b is E-shaped; that is, it comprises; a common base segment b.sub.1 ; and three lateral segments b.sub.2, b.sub.3 and b.sub.4 extended from the common base segment in the same direction. More specifically, the two lateral segments b.sub.3 and b.sub.4 are extended from both ends of the base segment b.sub.1, and the remaining lateral segment b.sub.2 is extended from the middle of the base segment so as to define two wire accommodating grooves c.sub.1 and c.sub.4 with the lateral segments b.sub.3 and b.sub.4. The lateral segments b.sub.2 through b.sub.4 have engaging protrusions b.sub.5 at the ends, respectively, and the common base segment b.sub.1 has a locking arm b.sub.6.
The terminal locking device is used as follows:
As shown in FIG. 9, for instance four metal terminals e connected to four electrical wires d are inserted and locked in terminal accommodating chambers a.sub.1 in advance. The electrical wires d inserted into the wire accommodating grooves c.sub.1 and c.sub.2 of the terminal locking element b, respectively. Under this condition, the terminal locking element b is pushed into an accommodating chamber a.sub.2 while being held inclined with the engaging protrusion b.sub.5 down, until the engaging protrusions are engaged with locking holes a.sub.3, respectively. Under this condition, the opposite end of the terminal locking element b is depressed until the locking arm b.sub.6 is engaged with a locking hole a.sub.4.
As was described above, the terminal locking element b is engaged with the accommodating chamber a.sub.2 from behind the housing a. It takes time to remove the terminal locking element from the housing.
The terminal locking element which is provided in addition to the connector housing, and is engaged with the connector housing from behind is a secondary locking means which is used to increase the terminal holding force, and to prevent the loose engagement of the terminals. Therefore, if a sufficient terminal holding force can be obtained by the primary locking of the connector housing, then all that is necessary for the terminal locking element is to prevent the loose engagement of the terminals.
On the other hand, there is a tendency for connectors to increase the number of poles. Therefore, a relatively great force is required for engaging the terminal locking element with the connector housing while driving a number of metal terminals forward which are not completely engaged with the housing.